[amsat-bb] Geostationary & HEO Satellites

[Simon Brown]

Paul,

 

The round trip with people I speak to would be several minutes 😊 .

 

Simon Brown, G4ELI
 <http://www.sdr-radio.com/> www.sdr-radio.com 

 

 

From: Paul Andrews <w2hro.fn20 at gmail.com> 
Sent: 08 February 2019 21:20
To: Simon Brown <simon at sdr-radio.com>
Cc: amsat-bb <amsat-bb at amsat.org>
Subject: Re: [amsat-bb] Geostationary & HEO Satellites

 

Simon,

 

I spent 20 years building data circuits using geosynchronous satellites.  During that time, my definition of round trip was uplink-dowlink-uplink-downlink or 4 x 150ms (plus or minus a small amount of Doppler).

 

Yes - you're correct - the loopback delay is 300ms.  But if you communicate with another person on Earth, the round trip delay is 600ms.

 

If you tell someone a joke, you won't hear the laugh until after a 600ms delay.  This is only true for a good joke.  Tell a bad joke and the delay will be infinite.  :O

 

73 - Paul - W2HRO

 

 

 

 

On Fri, Feb 8, 2019, 16:09 Simon Brown <simon at sdr-radio.com <mailto:simon at sdr-radio.com> > wrote:

Paul,

Unless there's significant latency inside the satellite, I think you're out by a factor of two. Round trip is 2 x 40,000 km (*) = 80,000 km total. Speed of light and radio latency says we're looking at closer to 300 ms.

(*) depending on where you are on the mother planet.

Simon Brown, G4ELI
www.sdr-radio.com <http://www.sdr-radio.com>  


-----Original Message-----
From: AMSAT-BB <amsat-bb-bounces at amsat.org <mailto:amsat-bb-bounces at amsat.org> > On Behalf Of Paul Andrews
Sent: 08 February 2019 19:27
To: Les Rayburn <les at highnoonfilm.com <mailto:les at highnoonfilm.com> >
Cc: AMSAT BB <amsat-bb at amsat.org <mailto:amsat-bb at amsat.org> >
Subject: Re: [amsat-bb] Geostationary & HEO Satellites

GEOSATs have another interesting characteristic.   600 ms round trip
delay due to the longer distance.

Does anyone remember when MCI first started providing a discounted long distance telephone service?

This will make voice QSOs a little unnatural but certainly not impossible.

73 - Paul - W2HRO





On Fri, Feb 8, 2019 at 12:21 PM Les Rayburn <les at highnoonfilm.com <mailto:les at highnoonfilm.com> > wrote:
>
> I’m also a newcomer to the birds, but very excited about it. Likewise, I responded to the survey, but wanted to comment further regarding geostationary and HEO satellites.
>
> In the camp of “Both, please.” The HEO birds would once again offer the possibility of DXCC and make WAS more realistic—it also offers more operating challenges.
>
> But a geostationary amateur satellite would have many interesting benefits:
>
> Provide an easier introduction to satellite operation, and attract new operators.
> Excellent tool for emergency communications during a natural disaster.
> Opportunity to experiment with microwave operations.
> The ability to enjoy satellite operation any time of the day/night. The band is always open.
>
> I’m grateful for anyone who incorporates amateur radio into their satellites, but feel that birds should include either linear, digital, or FM transponders whenever possible. Designers are asking a lot of hams when they solicit our monitoring their telemetry signals, and using amateur spectrum for their purposes without much tangible benefit to us. My opinion only.
>
> It’s wonderful that they asked us. Dialogue is the key to most human accomplishment.
>
>
> 73,
>
> Les Rayburn, N1LF
> Maylene, AL
> EM63nf
> AMSAT #38965, ARRL Life Member, CVHS Life Member, SVHF Member
>
>
>
>
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Sent via AMSAT-BB at amsat.org <mailto:AMSAT-BB at amsat.org> . AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA.
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_______________________________________________
Sent via AMSAT-BB at amsat.org <mailto:AMSAT-BB at amsat.org> . AMSAT-NA makes this open forum available
to all interested persons worldwide without requiring membership. Opinions expressed
are solely those of the author, and do not reflect the official views of AMSAT-NA.
Not an AMSAT-NA member? Join now to support the amateur satellite program!
Subscription settings: http://www.amsat.org/mailman/listinfo/amsat-bb